Heparinization is the treatment of choice for a number of pathological conditions. In general, it is critical that the heparin content of the blood be kept within certain limits, these limits depending on a number of variables. However, a major problem in heparin therapy is the absence of a rapid, sensitive technique for determining the concentration thereof in the blood. This situation prevails despite the fact that heparin has been used as an anticoagulant for over 30 years.
At the present time classical laboratory control depends upon the clotting time of whole blood or the activated partial thromboplastin time (APTT). Results are usually expressed as clotting times rather than as units of heparin in the circulating blood. Obviously, it is the latter quantity which is critical and which must serve as the basis for deciding how to proceed with further heparin therapy.
As is evident, a rapid, sensitive and reliable technique for determining heparin concentration would be highly desirable.